Adata XPG Gammix S50
PCIe Gen 4 and TLC memory for a price you can afford? Jeremy Laird would never fall for that old tale…
PCIe Gen 4 and TLC memory for a price you can afford? Jeremy Laird would never fall for that old tale…
We’re well through the early adopter stage of SSD PCIe4 technology, with numerous high-end PCIe 4.0 drives available, along with several value drives. The new ADATA XPG Gammix S50 Lite, sampled here in 2TB configuration and M.2 2280 format, falls into the latter category. But where some fourth-generation (Gen 4) drives achieve a lower price point by using cheap and not always terribly cheerful QLC or quad-level flash memory, ADATA has managed to price TLC or triple-level flash memory into the bargain – in this case, 96-layer Micron chips.
How has ADATA pulled off TLC at this kind of price point? The answer, at least in part, is a more affordable PCIe Gen 4 controller chip. The original Gammix S50 was a high-end PCIe Gen 4 drive with the Phison controller. This ‘Lite’ model is cheaper and powered by the new Silicon Motion SM2267 controller.
It’s the low-cost option from SM’s latest PCIe 4.0 controllers. It’s fabricated on a cheaper 28nm production node, where fancier controllers are made on 12nm or thereabouts. It’s also limited to four memory channels and two ARM Cortex R5 CPU cores. The SM2267’s SM sibling, for instance, is on 12nm, has eight memory channels and sports four Cortex R8 cores.
Doing more with less
That said, this new budget PCIe 4.0 controller is faster than SM’s previous-generation high-end
PCIe 3.0 controller, the SM2263, with 1,200MT/s peak performance to the older chip’s 800MT/s. What’s more, the increasing density of flash chips means you can achieve large capacities with just four channels, in this case fully 2TB. One other area of arguable cornercutting is cache allocation. The ADATA XPG Gammix S50 Lite gets 1GB of DDR4 cache where you might expect 2GB for a drive with 2TB of capacity. Still, a bit less DRAM is much better than no DRAM at all.
The official performance claims include sequential throughput of 3,900MB/s for reads and 3,200MB/s and for writes, while the 4K random access is pegged at 490K read IOPS and 540K write IOPS. Overall, then, the philosophy here is pretty straightforward. ADATA is aiming to achieve something akin to premium eightchannel PCIe third-generation performance drives such as the previous-generation WD Black SN750 or the Kioxia Exceria Plus, with a lower cost, quad-channel PCIe Gen 4 drive.
Rounding out the speeds, feeds and specs is 1,480TB of write endurance, which should be plenty for all but a tiny fringe of ultra-intense users, and a healthy five-year warranty. This 80mm M.2 drive gets a thin, flat heat spreader that claims to reduce temperatures by up to 20 per cent. All told, you’re looking at a cost of around three quarters that of a high-end PCIe Gen 4 drive with a more expensive eight-channel controller. So, it’s a pretty attractive proposition on paper.
But what about, you know, the performance? Peak performance in the most forgiving benchmark notching up 3.9GB/s reads and 3.2GB/s writes and are very much competitive with a high-end PCIe 3.0 drive.
As for 4K random access, again it depends on the application used. But the broad-brush conclusion is that the ADATA XPG Gammix S50 Lite 2TB returns numbers slightly above expectation, if not at all remarkable, at 71MB/s for reads and in the low- to mid-200s for writes.
Temperatures are very well managed, with a peak of just 53°C in testing. The well-managed temperatures imply that the drop from 1.1GB/s initial internal file copy speed to a fluctuating range between 300MB/s to 500MB/s after around 350GB of data is related to exhausting the SLC cache rather than thermal throttling. However, 3,300MB/s down to 500MB/s is rather lower than we would normally expect for TLC flash, so that aspect is inconclusive.